Extraskeletal osteosarcoma in right neck subcutaneous tissue: A case report of an extremely rare tumour.

Extraskeletal osteosarcoma (ESOS) is a rare soft-tissue sarcoma that is treated with surgical resection, chemotherapy and radiotherapy; however, as it is now considered to be radiation resistance, it is associated with conflicting management principles and poor outcomes. A multimodality approach is currently used to treat ESOS, which entails the incorporation of multidrug chemotherapy and/or radiotherapy coupled with surgery to obtain the best outcome; however, there are many factors that influence the treatment effects and clinical outcomes of ESOS. In the present study, a case of an 81-year-old man who suffered from primary ESOS in the subcutaneous tissue of the right-hand side of the neck was reported. The patient was treated several times with partial resection and once with radiotherapy, and was still living following 3 years of follow-up. Thus, the present case report demonstrated that surgical resection and postoperative radiotherapy regimens may be favourable in the short term with a disease-free survival of ~15 months; however, patients are prone to relapse.